Green Synthesis of Eco-Friendly Potassium Nanoparticles Immobilized Lipase Enzyme and its Potentials in Biodiesel Production

Abstract

Potassium Chloride and newbouldia laevis leaves extract were used for the synthesis of green potassium Nanoparticles (K-NPs) which were used to immobilize lipase from the germinating seeds of soya beans (Glycine max). The synthesized K-NPs were characterised by UV-visible spectrophotometry, Fourier transform infrared (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX). The UV- VIS spectroscopy absorbency peaks at 350 nm wavelength and 0.0275 absorbance. The FTIR revealed nine distinctive absorption bands which peaked at 799 -1273cm-1,1273 -1407 cm-1, 1610 -1847 cm-1, 2029 -2212 cm-1, 2454 -2539 cm-1, 2710 -2828 cm-1, 2997 -3063 cm-1, 3208 -3347 cm-1, and 799 -3818 cm-1. The SEM revealed particles that are amorphous in shape with no cluster or colony formation. The EDX showed high concentrations of elements like Tin, Vanadium and Titanium, moderate concentrations of Calcium, Sodium, Magnesium and Potassium, and a very low concentrations of Iron, Aluminium, Phosphorus, Silicon and Sulphur. The synthesized K-NPs were used to immobilize the lipase obtained from germinating seeds of soya beans. The K-NPs immobilized lipase was used in biodiesel production. The quality of the biodiesel produced by the K-NPs immobilized lipase mediated transesterification were investigated using the refractive index (RI), specific gravity (SG), Boiling point (B.Pt), and acid value (AV). The investigation revealed 1.4, 0.9 g/mL, 300 °C, and 0.6% m/m for RI, SG, B.Pt, AV respectively. The quantity of the biodiesel produced was investigated using Gas chromatography flame ionization detection (GCFID) and the result showed 68.5% content of the entire reaction mixture to be fatty acid methyl ester (FAME/Biodiesel). These results indicate that the biosynthesized K-NPs to be a complex molecule with high molecular mass; the quality and quantity of the biodiesel produced with K-NPs immobilized lipase competed with the world standard (ASTM 6751) for biodiesel.